Cant figure this one out?

[Alabama]

I have a 98 ranger, auto 3.0..i have owned the truck since new, within the last year some mornings when I leave for work at 4:30 it will turn over but will not start, I can try after the sun comes up a few hours later and it will crank and run perfectly all day, same thing the next morning with same effect, I have replaced plug wires, starter, coil pack, fuel filter,..what has me baffled is it's almost like it has its own schedule..what would cause this? Any ideas.. once it cranks it's perfectly fine, I can drive it all over the place stopping and starting..until the next morning, thanks

Also, when this occurs I can cycle the key numerous times and it still wont crank

 

[Shran]

it will turn over but will not start

Also, when this occurs I can cycle the key numerous times and it still wont crank

So just to be clear when this issue is happening, the engine will NOT turn over? Or it DOES turn over but won't fire?

No crank could be a lot of things, ignition switch, starter solenoid, ???

Crank and no fire could also be a lot of things but the early morning schedule sounds like it could be related to dew or humidity collecting on an electrical component.

 

[Alabama]

Thank you for the reply and yes when this occures it will turn over fine but will not fire off, I have checked all fuses etc, I will double check to make sure I don't see and exposed that could be getting wet.. I just can't understand why it only does it between certain hours only..and always before sunup..I will keep looking...what's so frustrating is when I get home from work after having to leave it due to the not running, it will crank and run fine, so it's a guessing game at this point, it makes troubleshooting the issue hard when it runs fine

 

[Dirtman]

Did it start doing this during the summer or have you noticed it during the colder months as well?

 

[rusty ol ranger]

Coolant temp sensor would be my guess.

 

[91stranger]

Are you hearing the fuel pump turn on when its not starting? ETC sensors are cheap and easy to replace. Wouldn't hurt to replace it. I would check plug connections on sensors like the MAF, IAC, ETC, inertia switch. Also check battery connections. Could be a little loose or corroded. Any engine codes???

 

[gw33gp]

91 stranger may be on to something with the fuel pump. Next time it doesn't start, cycle the ignition switch a few times. Turn to on without trying to start, leave it on a few second, turn off and repeat this cycle a few times. Then try to start it.
There is a check valve in he fuel pump that maintains fuel pressure when the engine is shut off. If the fuel pressure leaks down the fuel pump can't build up enough pressure to start the engine in one try.
It may not be your problem but it is an easy test.

 

[Ranger850]

your truck just don't do mornings. like my wife

 

[Alabama]

Thanks for the ideas guys but I narrowed it down to the fuel pump relay, I went to AutoZone and purchased one, came home after I looked at some schematics to figure out which one I thought it was and replaced it, after looking around at work today I seen a different schematic of the same fuse box...the relay I got from AutoZone is the correct relay for 99+, the relay I needed was the smaller relay #5, it's closer to the fenderwell on the driver's side, blower relationship is in the back left corner...I swapped the fuel pump and horn relay around and it fired right up ...not to jinx myself but I hope that fixed it..thanks again